The Night King also knew that the dragons would come. The Night King wanted a dragon...so he waited until he knew dragons were on the way before he allowed the attack to commence. That's why the heavy chains just happened to be there, all handy and whatnot. He knew. He waited. He got his dragon to break through the wall.

F*cking THIS!

WHAT was their plan to get over/through/across the wall IF Dragons weren't a thing?!

Pop Quiz Hotshot: Exactly HOW long were they trapped on that island? The dude runs aaaaaaaallll the way back to The Wall, THEN a raven is dispatched to fly south to deliver a message of ZOMG BRING DRAGONZ!!1!, THEN the Dragons have to fly NORTH to rescue our crew?

And that's the thing, we ALL knew that Jon & Co. were gonna be rescued by Dani and her dragons, once again, paint by numbers storytelling. We knew it was gonna happen. Because what else was gonna happen? NORMALLY Martin comes up with something that never occurred to us as viewers, but in this case as we're watching, we all know that EVENTUALLY the ZOMG DRAGONZ are gonna lay waste and save the f*ckin' day! A perfect example of this is Bron saving Jamie at the end of whatever episode it was when we weren't sure if Jamie was gonna lance Dani OR lance the dragon ORRRR if the dragon was gonna crispy-fry Jamie. We didn't know until that very last second what was gonna happen. THAT'S Martin storytelling.

Episode 7: ZOMG THOSE STARK GIRLS TOTALLY PWN3D LITTLEFINGER!!1! Geez, and after that super-heavy will she/won't she kill her sister confrontation from LAST episode I was totally convinced that they were gonna try and kill each other...you remember the interaction, it was the one that happened in a locked room where only the two of them and us as the audience were privy to it...anywho, apparently that whole conversation was totally staged in order to make Littlefi, um, I mean us as the audience think there was crazy murderous tension between the two of them. What. What? OHHHHHHH. I get it, storytelling unlike any other we've seen in the series...the sh*tty kind! Tension building with zero payoff? WTF?

THEN we learn that apparently their was a deleted scene in which the Redhaired Stark girl used Bran as a cctv...pry open his 3rd eye and tell her sh*t that's happened that didn't know happened, that we as an audience know happened because plot?

The showrunners are working off of Martin's "outline" for both books 7 and 8 NOT from the actual text, and thus, we're just getting super-poor, run of the mill, paint by numbers storytelling.

GoT WAS like Breaking Bad in that ANYTHING could happen at any time, expect the unexpected as it were, and thus, from one scene to the next, you never knew what exactly was gonna happen or how an event would unfold or who was gonna die. It's not like that anymore.

Examples:

Episode 6: while being trapped on a just large enough island! In the middle of a frozen lake, the walkers are alerted to the fact that the "moat" separating them from Jon & Crew is once again frozen-over because of a rock. A rock thrown by The Hound. Why? BECAUSE WE GOTTA MOVE THE PLOT!!1!